BRITISH MEDICAL JOURNAL
1250
6 Gotschlich, E C, Liu, T Y, and Artenstein, M S, Journal of Experimental Medicine, 1969, 129, 1349. Artenstein, M S, et al, Journal of Infectious Diseases, 1971, 124, 277. Greenwood, B M, Whittle, H C, and Dominic-Rajkovic, 0, Lancet, 1971, 2, 519. Greenwood, B M, and Whittle, H C, Journal of Infectious Diseases, 1974, 129, 201. o Edwards, E A, and Driscoll, W S, Proceedings of the Society for Experimental Biology and Medicine, 1967, 126, 876.
22 MAY 1976
Scott, D W, and Gershon, R K, Clinical and Experimental Immunology, 1970, 6, 313. Levine, L, et al, J3ournal of Pediatrics, 1960, 57, 836. Greenwood, B M, et al, Lacnet, 1972, 1, 169. 14 Doumas, B T, Watson, W A, and Biggs, H G, Clinica Chimica Acta, 1971, 31, 87. 15 Artenstein, M S, and Brandt, B L, 3rournal of Immunology, 1975, 115, 5. 16 Amsbaugh, D F, et al, J'ournal of Experimental Medicine, 1972, 136, 623. 17 Whisnant, J K, et al, Lancet, 1971, 2, 895.
12 13
Twenty-four hour monitoring of heart rate and activity in patients with diabetes mellitus: a comparison with clinic investigations T BENNETT, PATRICIA A RIGGOTT, D J HOSKING, J R HAMPTON British
Medical3Journal, 1976, 1,
1250-1251
Summary Heart rate and activity were recorded continuously in 11 selected diabetics during a normal day, and the observations were compared with results obtained in the same patients in the diabetic outpatient clinic 10 months earlier. Both sets of findings agreed well in heart rate variability and postural tachycardia. In patients with well-controlled diabetes simple tests of reflex cardiovascular control produce results that may be useful in following the course of diabetic autonomic neuropathy.
Introduction Simple measurements of heart rate variability and the changes in heart rate and blood pressure elicited by standing can distinguish different categories of autonomic dysfunction in patients with diabetes mellitus.' Nevertheless, it has hitherto been unknown to what extent these simple measurements, generally performed in the diabetic clinic, reflect the behaviour of the cardiovascular system during normal daily activity. We therefore monitored the heart rate and activity patterns of selected diabetics during a normal day and compared the findings with observations made 10-12 months earlier on the same subjects in the diabetic clinic. Patients and methods Eleven patients were selected from a series previously described1-3 to include various combinations of normal and abnormal sympathetic and parasympathetic function. Sympathetic function was considered intact if there was: (a) maintenance of blood pressure on standing (baroreflex activation of peripheral vasoconstrictor mechanisms) associated with a moderate tachycardia (baroreflex activation of cardiac
Department of Physiology and Pharmacology, University Hospital and Medical School, Nottingham NG7 2UH T BENNETT, BSC, PHD, lecturer in physiology PATRICIA A RIGGOTT, BA, medical technician Department of Medicine, General Hospital, Nottingham NG1 6HA D J HOSKING, MD, MRCP, senior medical registrar J R HAMPTON, DM, FRcP, consultant physician and reader
sympathetics)'; (b) constriction of forearm blood vessels in response to immersion of the face in water during breath-holding (trigeminal receptors in the facial area activating sympathetic vasoconstrictor nerves)2; (c) an overshoot in systemic arterial pressure after the Valsalva manoeuvre (baroreflex activation of peripheral vasoconstrictor mechanisms):'; and (d) tachycardia during performance of a mental task (central activation of cardiac sympathetics)2. Parasympathetic function was considered intact if there was: (a) pronounced sinus arrhythmia during deep breathing (peripheral and central activation of the cardiac vagus)l '; (b) bradycardia in response to immersion of the face in water during breath-holding (trigeminal receptors in the facial area activating the cardiac vagus)2; (c) bradycardia in response to systemic arterial hypertension after the Valsalva manoeuvre (baroreflex activation of the cardiac vagus)'3; and (d) bradycardia in response to systemic arterial hypertension after intravenous infusion of phenylephrine (baroreflex activation of the cardiac vagus). The patients fell into three groups: group 1 comprised four patients who showed the responses described above and were therefore judged to have intact sympathetic and parasympathetic mechanisms. In group 2 were four patients who showed no signs of cardiac vagal activity but who had intact or only slightly impaired peripheral sympathetic mechanisms. The three patients in group 3 showed no signs of vagal or peripheral vasoconstrictor activity, although cardiac sympathetic control appeared intact'; These patients showed considerable postural hypotension accompanied by a dramatic tachycardia.' The diabetes in all patients was well-controlled at the time of the study. Measurements in clinic-Heart rate variability during deep breathing4 and the changes in heart rate and systolic arterial blood pressure in response to standing for five minutes had been measured as des-
cribed.' Measurements under unrestricted conditions-The patients were visited at home between 9.00 am and 10.00 am on the day of observation. Chest electrodes were applied, and the electrocardiogram (ECG) recorded from these was fed into one channel of a body-borne tape recorder (Oxford Instruments). A pedometer5 capable of distinguishing sustained activity, intermittent activity, and standing was fitted to one foot of the patient and the output was fed into another channel of the tape recorder. Patients were also given diary cards to fill in with information about specific activities. The recording was continued for 24 hours. The tape recorder, pedometer, and diary card were collected the next day. The tapes were played back at 25 times real time, the ECG being passed through a ratemeter to give a value for instantaneous heart rate. ECG, heart rate, and pedometer output were recorded on an ultraviolet monitor. By reference to the pedometer output and diary cards the continuous heart rate recording was examined in terms of the patient's activities.
Results The mean heart rate of the subjects in group 3 was higher than that of those in groups 1 and 2, although during sleep or while sitting the
22 MAY 1976
BRITISH MEDICAL JOURNAL
1251
TABLE I-Mean (+SE of mean) heart rates (beatslmin) during sleep, after rising (standing), while sitting, and during intermittent or sustained activity
Group 1. Group 2
Group3388-0 ± 66
Sleeping
Just before rising
15 s after
790 ± 6-0 75-5 + 6-0
85-5 ± 6-0 81-0-± 5-4 907 ±- 53
96-0 ± 6-7 92-5 ± 6-8 1067 4: 33
1 min after rising
rising
101-5 95-5 1210
6-0 4-2 46
5 min after
Sitting
Working intermittently
Working continuously
99 5 ± 6-0 94-3 + 4 9 1233 ± 30
90-0 1 5 0 89-0 ± 4-3 907 ± 68
103-2 ± 7-5 105-0 ± 5-3 1120 ± 93
124-7 .± 6-5 123-0 i 40 1350 ± 100
rising
Differences between mean heart rates for groups 1 and 2 compared with group 3 were significant (P
1250
6 Gotschlich, E C, Liu, T Y, and Artenstein, M S, Journal of Experimental Medicine, 1969, 129, 1349. Artenstein, M S, et al, Journal of Infectious Diseases, 1971, 124, 277. Greenwood, B M, Whittle, H C, and Dominic-Rajkovic, 0, Lancet, 1971, 2, 519. Greenwood, B M, and Whittle, H C, Journal of Infectious Diseases, 1974, 129, 201. o Edwards, E A, and Driscoll, W S, Proceedings of the Society for Experimental Biology and Medicine, 1967, 126, 876.
22 MAY 1976
Scott, D W, and Gershon, R K, Clinical and Experimental Immunology, 1970, 6, 313. Levine, L, et al, J3ournal of Pediatrics, 1960, 57, 836. Greenwood, B M, et al, Lacnet, 1972, 1, 169. 14 Doumas, B T, Watson, W A, and Biggs, H G, Clinica Chimica Acta, 1971, 31, 87. 15 Artenstein, M S, and Brandt, B L, 3rournal of Immunology, 1975, 115, 5. 16 Amsbaugh, D F, et al, J'ournal of Experimental Medicine, 1972, 136, 623. 17 Whisnant, J K, et al, Lancet, 1971, 2, 895.
12 13
Twenty-four hour monitoring of heart rate and activity in patients with diabetes mellitus: a comparison with clinic investigations T BENNETT, PATRICIA A RIGGOTT, D J HOSKING, J R HAMPTON British
Medical3Journal, 1976, 1,
1250-1251
Summary Heart rate and activity were recorded continuously in 11 selected diabetics during a normal day, and the observations were compared with results obtained in the same patients in the diabetic outpatient clinic 10 months earlier. Both sets of findings agreed well in heart rate variability and postural tachycardia. In patients with well-controlled diabetes simple tests of reflex cardiovascular control produce results that may be useful in following the course of diabetic autonomic neuropathy.
Introduction Simple measurements of heart rate variability and the changes in heart rate and blood pressure elicited by standing can distinguish different categories of autonomic dysfunction in patients with diabetes mellitus.' Nevertheless, it has hitherto been unknown to what extent these simple measurements, generally performed in the diabetic clinic, reflect the behaviour of the cardiovascular system during normal daily activity. We therefore monitored the heart rate and activity patterns of selected diabetics during a normal day and compared the findings with observations made 10-12 months earlier on the same subjects in the diabetic clinic. Patients and methods Eleven patients were selected from a series previously described1-3 to include various combinations of normal and abnormal sympathetic and parasympathetic function. Sympathetic function was considered intact if there was: (a) maintenance of blood pressure on standing (baroreflex activation of peripheral vasoconstrictor mechanisms) associated with a moderate tachycardia (baroreflex activation of cardiac
Department of Physiology and Pharmacology, University Hospital and Medical School, Nottingham NG7 2UH T BENNETT, BSC, PHD, lecturer in physiology PATRICIA A RIGGOTT, BA, medical technician Department of Medicine, General Hospital, Nottingham NG1 6HA D J HOSKING, MD, MRCP, senior medical registrar J R HAMPTON, DM, FRcP, consultant physician and reader
sympathetics)'; (b) constriction of forearm blood vessels in response to immersion of the face in water during breath-holding (trigeminal receptors in the facial area activating sympathetic vasoconstrictor nerves)2; (c) an overshoot in systemic arterial pressure after the Valsalva manoeuvre (baroreflex activation of peripheral vasoconstrictor mechanisms):'; and (d) tachycardia during performance of a mental task (central activation of cardiac sympathetics)2. Parasympathetic function was considered intact if there was: (a) pronounced sinus arrhythmia during deep breathing (peripheral and central activation of the cardiac vagus)l '; (b) bradycardia in response to immersion of the face in water during breath-holding (trigeminal receptors in the facial area activating the cardiac vagus)2; (c) bradycardia in response to systemic arterial hypertension after the Valsalva manoeuvre (baroreflex activation of the cardiac vagus)'3; and (d) bradycardia in response to systemic arterial hypertension after intravenous infusion of phenylephrine (baroreflex activation of the cardiac vagus). The patients fell into three groups: group 1 comprised four patients who showed the responses described above and were therefore judged to have intact sympathetic and parasympathetic mechanisms. In group 2 were four patients who showed no signs of cardiac vagal activity but who had intact or only slightly impaired peripheral sympathetic mechanisms. The three patients in group 3 showed no signs of vagal or peripheral vasoconstrictor activity, although cardiac sympathetic control appeared intact'; These patients showed considerable postural hypotension accompanied by a dramatic tachycardia.' The diabetes in all patients was well-controlled at the time of the study. Measurements in clinic-Heart rate variability during deep breathing4 and the changes in heart rate and systolic arterial blood pressure in response to standing for five minutes had been measured as des-
cribed.' Measurements under unrestricted conditions-The patients were visited at home between 9.00 am and 10.00 am on the day of observation. Chest electrodes were applied, and the electrocardiogram (ECG) recorded from these was fed into one channel of a body-borne tape recorder (Oxford Instruments). A pedometer5 capable of distinguishing sustained activity, intermittent activity, and standing was fitted to one foot of the patient and the output was fed into another channel of the tape recorder. Patients were also given diary cards to fill in with information about specific activities. The recording was continued for 24 hours. The tape recorder, pedometer, and diary card were collected the next day. The tapes were played back at 25 times real time, the ECG being passed through a ratemeter to give a value for instantaneous heart rate. ECG, heart rate, and pedometer output were recorded on an ultraviolet monitor. By reference to the pedometer output and diary cards the continuous heart rate recording was examined in terms of the patient's activities.
Results The mean heart rate of the subjects in group 3 was higher than that of those in groups 1 and 2, although during sleep or while sitting the
22 MAY 1976
BRITISH MEDICAL JOURNAL
1251
TABLE I-Mean (+SE of mean) heart rates (beatslmin) during sleep, after rising (standing), while sitting, and during intermittent or sustained activity
Group 1. Group 2
Group3388-0 ± 66
Sleeping
Just before rising
15 s after
790 ± 6-0 75-5 + 6-0
85-5 ± 6-0 81-0-± 5-4 907 ±- 53
96-0 ± 6-7 92-5 ± 6-8 1067 4: 33
1 min after rising
rising
101-5 95-5 1210
6-0 4-2 46
5 min after
Sitting
Working intermittently
Working continuously
99 5 ± 6-0 94-3 + 4 9 1233 ± 30
90-0 1 5 0 89-0 ± 4-3 907 ± 68
103-2 ± 7-5 105-0 ± 5-3 1120 ± 93
124-7 .± 6-5 123-0 i 40 1350 ± 100
rising
Differences between mean heart rates for groups 1 and 2 compared with group 3 were significant (P
